Permafrost thaw and climate warming may decrease the CO2, carbon, and metal concentration in peat soil waters of the Western Siberia Lowland

Soil pore waters are a vital component of the ecosystem as they are efficient tracers of mineral weathering, plant litter leaching, and nutrient uptake by vegetation. In the permafrost environment, maximal hydraulic connectivity and element transport from soils to rivers and lakes occurs via supra-permafrost flow (i.e. water, gases, suspended matter, and solutes migration over the permafrost table). To assess possible consequences of permafrost thaw and climate warming on carbon and Green House gases (GHG) dynamics we used a “substituting space for time” approach in the largest frozen peatland of the world. We sampled stagnant supra-permafrost (active layer) waters in peat columns of western Siberia Lowland (WSL) across substantial gradients of climate (−4.0 to −9.1 °C mean annual temperature, 360 to 600 mm annual precipitation), active layer thickness (ALT) (>300 to 40 cm), and permafrost coverage (sporadic, discontinuous and continuous). We analyzed CO2, CH4, dissolved carbon, and major and trace elements (TE) in 93 soil pit samples corresponding to several typical micro landscapes constituting the WSL territory (peat mounds, hollows, and permafrost subsidences and depressions)